The present invention relates to a computerized numerical control automatic complex lathe having a main spindle and a back spindle. More particularly, the present invention relates to an improvement adapted to increase the number of work processes performed on the back spindle thereby enhancing the utility of back spindle.
A conventional computerized numerical control automatic complex lathe, having a main spindle and a back spindle is known. The main spindle is constructed to grip a rod-shaped work in a work chuck so that the work can be rotated and machined for machining it and rotating it. The back spindle is positioned on the side facing the main spindle via the work and in parallel to the main spindle. On the work side of back spindle is integrally fixed a machining chuck as a back spindle tool.
The above-described computerized numerical control automatic complex lathe is so constructed that a rod-shaped work gripped in the machining chuck on the main spindle is machined with a cutting tool for main machining or a machining tool on a turret tool rest, and after the work is regripped in the work chuck on the back spindle, the work is machined with a machining tool as described above while being gripped in this chuck.
With the above-described conventional computerized numerical control automatic complex lathe, it is impossible to change the chuck on the work back spindle without stopping the machine. Also during cutting, only one kind of work that matches the chuck can be gripped. Also, a tool other than a chuck, for example a drill, cannot be mounted on the back spindle. Therefore, the work process which can be performed by the back spindle is limited to gripping only one kind of work.